He also alleged in recent Senate estimates hearings that a royal commission had overlooked a list of 28 "alleged paedophiles" including a former prime minister, which ex-commissioner and judge James Wood denied.

Independent senator Nick Xenophon said Senator Heffernan had been prepared to fight against his own party on policies involving regional Australia: "He cuts through the crap."

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The pair in 2011 pushed for a review of quarantine laws and opposed allowing pork imports from countries with porcine reproductive and respiratory syndrome.

"He's been a champion for the bush and for our farmers. He's been a truth-teller when it comes to issues of successive government policies when it comes to farm land, whether it's biosecurity, investing in agriculture or managed investment schemes."

Senator Xenophon would continue to seek his advice on regional issues after he had left Parliament, saying others would be "foolish" not to: "I don't think anyone in Parliament has that level of cut-through common sense when it comes to regional issues."

Labor senator Glenn Sterle, who co-chaired the Senate standing committee on rural and regional affairs with Senator Heffernan for 11 years, said he would miss working with him, despite some of his "disgraceful" antics, citing his calling former prime minister Julia Gillard "deliberately barren".

"There are certain aspects of his gruffness that won't be missed, but at the end of the day Bill Heffernan never let anyone wonder what the hell he was thinking," Senator Sterle said. "He ruffled a few feathers and the Liberal Party will find no one who could be as representative of rural Australia as he has been."

Senator Heffernan had also supported greater transparency of foreign investment regimes and spoken out against outsourcing Australian shipping jobs.

It comes as Parliament is set to lose more than 350 years of combined experience, with about 19 people, including cabinet ministers, expected to depart this year.